Enrichment in the normalizer

When creating event parsing rules in the normalizer settings window, on the Enrichment tab, you can configure the rules for adding extra data to the fields of the normalized event using enrichment rules. These enrichment rules are stored in the settings of the normalizer where they were created.

Enrichments are created by using the Add enrichment button. There can be more than one enrichment rule. You can delete enrichment rules by using the button.

Settings available in the enrichment rule settings block:

• Source kind (required)—drop-down list for selecting the type of enrichment. Depending on the selected type, you may see advanced settings that will also need to be completed.

  Available Enrichment rule source types:

  • constant

    This type of enrichment is used when a constant needs to be added to an event field. Settings of this type of enrichment:

    • In the Constant field, specify the value that should be added to the event field. The value may not be longer than 255 Unicode characters. If you leave this field blank, the existing event field value will be cleared.
    • In the Target field drop-down list, select the KUMA event field to which you want to write the data.

  • dictionary

    This type of enrichment is used if you need to add a value from the dictionary of the Dictionary type.

    When this type is selected in the Dictionary name drop-down list, you must select the dictionary that will provide the values. In the Key fields settings block, you must use the Add field button to select the event fields whose values will be used for dictionary entry selection.

  • table

    This type of enrichment is used if you need to add a value from the dictionary of the Table type.

    When this enrichment type is selected in the Dictionary name drop-down list, select the dictionary for providing the values. In the Key fields group of settings, use the Add field button to select the event fields whose values are used for dictionary entry selection.

    In the Mapping table, configure the dictionary fields to provide data and the event fields to receive data:

    • In the Dictionary field column, select the dictionary field. The available fields depend on the selected dictionary resource.
    • In the KUMA field column, select the event field to which the value is written. For some of the selected fields (*custom* and *flex*), in the Label column, you can specify a name for the data written to them.

    New table rows can be added by using the Add new element button. Columns can be deleted using the button.

  • event

    This type of enrichment is used when you need to write a value from another event field to the current event field. Settings of this type of enrichment:

    • In the Target field drop-down list, select the KUMA event field to which you want to write the data.
    • In the Source field drop-down list, select the event field whose value will be written to the target field.
    • Clicking the button opens the Conversion window in which you can, using the Add conversion button, create rules for modifying the original data before writing them to the KUMA event fields.

      Available conversions

      Conversions are changes that can be applied to a value before it gets written to the event field. The conversion type is selected from a drop-down list.

      Available conversions:

      • lower—is used to make all characters of the value lowercase
      • upper—is used to make all characters of the value uppercase
      • regexp – used to convert a value using the regular expression RE2. When this conversion type is selected, the field appears where regular expression should be added.
      • substring—is used to extract characters in the position range specified in the Start and End fields. These fields appear when this conversion type is selected.
      • replace—is used to replace specified character sequence with the other character sequence. When this type of conversion is selected, new fields appear:
        • Replace chars—in this field you can specify the character sequence that should be replaced.
        • With chars—in this field you can specify the characters sequence should be used instead of replaced characters.
      • trim—used to simultaneously remove the characters specified in the Chars field from the leading and end positions of the value. The field appears when this type of conversion is selected. For example, a trim conversion with the Micromon value applied to Microsoft-Windows-Sysmon results in soft-Windows-Sys.
      • append is used to add the characters specified in the Constant field to the end of the event field value. The field appears when this type of conversion is selected.
      • prepend—used to prepend the characters specified in the Constant field to the start of the event field value. The field appears when this type of conversion is selected.
      • replace with regexp—is used to replace RE2 regular expression results with the character sequence.
        • Expression—in this field you can specify the regular expression which results that should be replaced.
        • With chars—in this field you can specify the characters sequence should be used instead of replaced characters.
      • Converting encoded strings to text:
        • decodeHexString—used to convert a HEX string to text.
        • decodeBase64String—used to convert a Base64 string to text.
        • decodeBase64URLString—used to convert a Base64url string to text.

        When converting a corrupted string or if conversion error occur, corrupted data may be written to the event field.

        During event enrichment, if the length of the encoded string exceeds the size of the field of the normalized event, the string is truncated and is not decoded.

        If the length of the decoded string exceeds the size of the event field into which the decoded value is to be written, such a string is truncated to fit the size of the event field.

  • template

    This type of enrichment is used when you need to write a value obtained by processing Go templates into the event field. Settings of this type of enrichment:

    • Put the Go template into the Template field.

      Event field names are passed in the {{.EventField}} format, where EventField is the name of the event field from which the value must be passed to the script.

      Example: Attack on {{.DestinationAddress}} from {{.SourceAddress}}.

    • In the Target field drop-down list, select the KUMA event field to which you want to write the data.
• Target field (required)—drop-down list for selecting the KUMA event field that should receive the data.

  This setting is not available for the enrichment source of the Table type.